MOSCOW, Russia—German Chancellor Angela Merkel and Russian President Vladimir Putin reaffirmed their sharply different views of Russia’s treatment of imprisoned Kremlin critic Alexei Navalny, democratic values, and other major topics of dispute Friday but vowed to maintain a dialogue. Merkel traveled to Moscow as she is nearing the end of her almost 16-year-long leadership of Germany. Despite deep disagreements, she has tried throughout her tenure to preserve close contacts with Putin, who has been in power for more than two decades. Their meeting Friday came on the anniversary of Navalny falling gravely ill on a domestic flight over Siberia from what European officials would later say was poisoning with a Soviet-developed nerve agent. After the opposition leader was stricken, he was flown to Germany for medical treatment at his wife’s insistence and spent five months there recuperating. Navalny, who is Putin’s most outspoken critic blamed the Aug. 20, 2020 attack …